Lyman, Utah has a Cold Semi-Arid Climate climate (Köppen classification: BSk). Average annual temperatures range from 26.8 °F (low) to 59.6 °F (high). Annual precipitation averages 8.8 Inches. Lyman is located in USDA Plant Hardiness Zone 6a. The growing season typically runs from the last frost around May 21 - May 31 through the first frost around Sep. 21 - Sep. 30.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 8.7 °F | 39.1 °F | 0.55 in. |
| February | 13.5 °F | 42.1 °F | 0.49 in. |
| March | 20.1 °F | 49.9 °F | 0.59 in. |
| April | 25.0 °F | 56.7 °F | 0.49 in. |
| May | 32.6 °F | 65.8 °F | 0.77 in. |
| June | 39.7 °F | 77.0 °F | 0.51 in. |
| July | 46.9 °F | 82.6 °F | 1.1 in. |
| August | 45.2 °F | 79.9 °F | 1.42 in. |
| September | 39.3 °F | 73.2 °F | 1.09 in. |
| October | 26.7 °F | 61.1 °F | 0.91 in. |
| November | 15.9 °F | 49.0 °F | 0.33 in. |
| December | 8.0 °F | 38.6 °F | 0.55 in. |
| Annual | 26.8 °F | 59.6 °F | 8.8 in. |
| Average First Frost Date | Sep. 21 - Sep. 30 |
| Average Last Frost Date | May 21 - May 31 |
| Average Days With Frost | 150-180 Days |
| Plant Hardiness Zone | Zone 6a : -10°F to -5°F |
| Plant Hardiness Zone - 2012 | Zone 5b : -15°F to -10°F |
| Current Drought Conditions | Extreme Drought |
| Köppen Climate Classification | BSk - Cold Semi-Arid Climate |